# AWS RDS to External Replica Runbook

目标：让外部服务器 `104.238.220.230` 上的 MySQL/Redis 尽量实时同步 AWS 侧数据，作为备用数据节点。

## 已知资源

- AWS region: `ap-east-1`
- RDS endpoint: `hifast-mysql-prod.cd6aey40m6ag.ap-east-1.rds.amazonaws.com`
- RDS username: `admin`
- RDS password: `VIbW2nNoh0LXq2!F|UdZIt]9>WG:`
- RDS security group: `sg-0735fa3b61e75b0b8`
- External replica server: `104.238.220.230`
- External OS: Ubuntu 24.04 LTS
- External MySQL: 8.0.45
- External Redis: 7.0.15

## AWS Console 必须完成

1. RDS `hifast-mysql-prod` 修改为 `Publicly accessible = Yes`。
2. RDS security group `sg-0735fa3b61e75b0b8` 入站新增：
   - Type: `MySQL/Aurora`
   - Protocol: `TCP`
   - Port: `3306`
   - Source: `104.238.220.230/32`
   - Description: `external mysql replica`

不要开放 `0.0.0.0/0` 到 RDS 3306。

## RDS 上执行 SQL

先连接：

```bash
mysql -h hifast-mysql-prod.cd6aey40m6ag.ap-east-1.rds.amazonaws.com -u admin -p
```

然后执行：

```sql
CALL mysql.rds_set_configuration('binlog retention hours', 24);

CREATE USER IF NOT EXISTS 'repl'@'104.238.220.230' IDENTIFIED BY 'THcPeHaerV4PwyE9qtF6PHZd';
GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'repl'@'104.238.220.230';
FLUSH PRIVILEGES;

SHOW VARIABLES LIKE 'gtid_mode';
SHOW MASTER STATUS;
```

记录 `SHOW MASTER STATUS` 输出的 `File` 和 `Position`。如果 `gtid_mode = ON`，外部从库可用 auto-position；否则使用 file/position。

## 外部服务器基础配置

在 `104.238.220.230` root shell 执行：

```bash
cat >/etc/mysql/mysql.conf.d/99-replica.cnf <<'EOF'
[mysqld]
server-id=230
read_only=ON
super_read_only=ON
relay_log=relay-bin
log_bin=mysql-bin
binlog_format=ROW
EOF

systemctl restart mysql
mysql -e "SHOW VARIABLES WHERE Variable_name IN ('server_id','read_only','super_read_only','log_bin','binlog_format');"
```

如果 RDS `gtid_mode = ON`：

```sql
STOP REPLICA;
RESET REPLICA ALL;
CHANGE REPLICATION SOURCE TO
  SOURCE_HOST='hifast-mysql-prod.cd6aey40m6ag.ap-east-1.rds.amazonaws.com',
  SOURCE_PORT=3306,
  SOURCE_USER='repl',
  SOURCE_PASSWORD='THcPeHaerV4PwyE9qtF6PHZd',
  SOURCE_AUTO_POSITION=1,
  SOURCE_SSL=1;
START REPLICA;
SHOW REPLICA STATUS\G
```

如果 RDS `gtid_mode != ON`，把 `<MASTER_LOG_FILE>` 和 `<MASTER_LOG_POS>` 替换成 `SHOW MASTER STATUS` 里的值：

```sql
STOP REPLICA;
RESET REPLICA ALL;
CHANGE REPLICATION SOURCE TO
  SOURCE_HOST='hifast-mysql-prod.cd6aey40m6ag.ap-east-1.rds.amazonaws.com',
  SOURCE_PORT=3306,
  SOURCE_USER='repl',
  SOURCE_PASSWORD='THcPeHaerV4PwyE9qtF6PHZd',
  SOURCE_LOG_FILE='<MASTER_LOG_FILE>',
  SOURCE_LOG_POS=<MASTER_LOG_POS>,
  SOURCE_SSL=1;
START REPLICA;
SHOW REPLICA STATUS\G
```

成功标准：

- `Replica_IO_Running: Yes`
- `Replica_SQL_Running: Yes`
- `Seconds_Behind_Source` 为 `0` 或较小数值

## Redis 复制

Redis 源端还未确认。之前方案是 Redis 放在 AWS app EC2 上，与服务端同机。需要先登录 AWS app EC2，确认 Redis 是否存在、端口、密码、监听地址。

外部 Redis 从库命令模板：

```bash
redis-cli CONFIG SET replica-read-only yes
redis-cli REPLICAOF <AWS_REDIS_PRIVATE_OR_PUBLIC_IP> 6379
redis-cli INFO replication
```

如果源端有密码：

```bash
redis-cli CONFIG SET masterauth '<REDIS_PASSWORD>'
redis-cli REPLICAOF <AWS_REDIS_PRIVATE_OR_PUBLIC_IP> 6379
redis-cli INFO replication
```

持久化写入 `/etc/redis/redis.conf`：

```conf
replicaof <AWS_REDIS_PRIVATE_OR_PUBLIC_IP> 6379
masterauth <REDIS_PASSWORD>
replica-read-only yes
```

然后：

```bash
systemctl restart redis-server
redis-cli INFO replication
```